Safe starting system for lawn and garden equipment

ABSTRACT

A riding mower has an internal combustion engine with a magneto type ignition system and a recoil starter. A mower is suspended from the tractor and driven from the engine through a belt drive, which includes a clutch, while the traction wheels are driven through a different drive system, which also includes a clutch. A pair of parallel connected switches are respectively connected to the clutches so that they close when the clutches are engaged, and the switches are connected to the magneto primary coil and a normally closed centrifugal switch, which is disposed between the engine flywheel and the recoil starting mechanism and opens only when the engine reaches a predetermined speed. When the centrifugal switch is closed and either of the clutch switches are closed, the magneto primary is shorted to ground, preventing the starting of the engine when either of the clutches is engaged. When the engine reaches the predetermined speed, the centrifugal switch opens, so that either clutch can be engaged without shorting out the magneto primary coil.

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I i Unite States Patent 1 1 3,731,471

Bening 1 May 8, 1973 [54] SAFE STARTING SYSTEM FOR LAWN AND GARDENEQUIPMENT [57] ABSTRACT [75] Inventor: Curtis Reinhard Bening, Burnett,A riding mower has an internal combustion engine Wis. with a magnetotype ignition :system and a recoil starter. A mower is suspended fromthe tractor and [73] Asslgnee' Deere & Company Molme driven from theengine through a belt drive, which in- [22] Filed: Mar. 22, 1972 cludesa clutch, while the traction wheels are driven through a different drivesystem which also includes a l. N [211 236909 clutch. A pair of parallelconnected switches are respectively connected to the clutches so thatthey 1 180/53 R close when the clutches are engaged, and the switches[51] Int. Cl. ..A0ld 75/18 are nne t d to the magneto primary coil and anor [58] Field 0188811211 ..56/10.2, 10.5, DIG. 15; mally closedcentrifugal witch, which is disposed /53 192/84 between the engineflywheel and the recoil starting mechanism and opens only when theengine reaches a 1' References Cited predetermined speed. When thecentrifugal switch is closed and either of the clutch switches areclosed, the UNITED STATES PATENTS magneto primary is shorted to ground,preventing the 3,169,358 5/1965 Ertsgaard et al. ..56/l0.5 starting ofthe engine when either of the clutches is 3,229,452 H1966 Has n ank..56/l0.5 engaged. When the engine reaches the predetermined peed theentrifugal witch opens 50 that either 3,626,676 12/1971 Miley et a1..56/10.5 clutch can be engaged without shorting out the neto primarycoil. Primary ExaminerAntonio F. Guida Att0rneyH. Vincent Harsha et al.10 Claims, 2 Drawing Figures P atnted May 8, 1973 3,731,411

FIG.2

SAFE STARTING SYSTEM FOR LAWN AND GARDEN EQUIPMENT BACKGROUND OF THEINVENTION traction drive or the drive to the working implement, is lengaged.

With the increasing use of powered lawn and garden equipment, such asriding lawn mowers, lawn and garden tractors, rotary tillers, or snowblowers, there has been increased concern regarding the safety of suchmachines. Manyof such machines utilize'an internal combustion enginestarted with a recoil starter, and generally it is necessary for theoperator to leavethe controls of the machine to start the engine. If theengine is started with any of the drive clutches engaged, such as themain traction drive or the mower drive in the case of a riding lawnmower, there is an obvious SUMMARY OF THE INVENTION According to thepresent invention, an improved safe starting system is provided for lawnand garden equip ment, such as riding mowers or the like. Moreparticularly, there is provided a safe starting system utilizing clutchactuated switches, which short theignition when one of the driveclutches is engaged unless the engine is rotating above a predeterminedspeed, a centrifugal switch being disposed in the grounding circuit androtating with the engine so that it opens when a predetermined speed isreached to interrupt the grounding circuit.

Also according to the invention, the centrifugal switch is mounted onthe engine flywheel for rotation therewith between the flywheel and arecoil starter.

An important advantage of the invention resides in the'fact that thecentrifugal switch is in a protected location, so that it cannot bemanually overridden.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view of ariding mower in which the invention is embodied.

FIG. 2 is a schematic view of-the safe starting system, including asectional view of the engine recoil starting mechanism and a portion ofthe flywheel.

DESCRIPTION OF THE PREFERRED EMBODIMENT control lever 22 projects fromthe right side of the enclosure for manipulation by a seated operator.An

inclined steering pedestal 24 extends upwardly and rearwardly from thefront end of the main frame and supports a steering handle 26 whichcontrols the position of the front wheels 14.

A mower unit, indicated in its entirety by the numeral 28, is suspendedfrom the main frame between the front and rear drive wheels 12 and 14 bymeans ofa suspension linkage 29. The mower unit 28 is-of the well-knownrotary type, and includes rotating horizontal blades, which are drivenfrom the engine by a conventional belt drive (not shown). As is alsowell known, the drive to the mower unit is selectively engageable ordisengageable by shifting a pulley, which controls the tension of thedrive belt. The pulley is moved to tension the drive belt by depressinga clutch pedal 30 pivotally mounted on the main frame on the right sideof the steering pedestal 24, the clutch beingreleased or disengaged bydepressing a clutch release pedal mounted adjacent to the clutch pedal30. The above described clutching mechanism for the mower drive isdescribed in detail in said U. S. Pat. Nos. 3,608,285 and 3,626,676.

As is also well known, a decluitchable belt drive is utilized totransmit the driving torque from the engine to the propulsiontransmission (not shown). The propulsion drive is disengaged bydepressing a clutch pedal 34, which is shown only in FIG. 2, since it ismounted on the left side of the pedestal 24 and not visible in FIG. 1.The depression of the pedal'34 initially disengages the clutch, andfurther depression of the pedal actuates a braking mechanism, as alsodescribed the upper end of the output shaft by means of a nut 40. Aconventional recoil starter 42 is mounted on top of the engine housing36 above the flywheel 38 and includes a housing 44 secured to the top ofthe engine housing by means of bolts 46 extending through both' housingsand secured therein 'by "nuts 48. Insulated washers 50 are providedbetween the bolt heads and the starter housing 44 and also between thestarter housing 44 and the engine housing 36. The starter 42 alsoincludes a starter rope 52 wound on a pulley 54 secured to a shaft 56,which is rotatable relative to the starter housing 44 while electricallyconnected thereto The rope extends tangentially through the housing andhas a handle 57 on its exterior end.

A hub 58 is attached to the starter shaft 56 and is rotatable within acup-like element 60 clamped to. the

flywheel 38 by the nut 40.'As is well known, pulling on the rope causesa driving lug or dog (not shown) on the 1 hub 58 to engage an abutment(also not shown) on the cup to form a one-way driving connection betweenthe hub and the flywheel which causes the engine to turn when the ropeis pulled.

A centrifugal switch element 62 is clamped between: the cup 60 and thenut 40 and includes an upwardly extending spring-like arm 63 having ahemispherical con- I tact 64 at its upper end. When the flywheel is notrotating, the arm is in its closed position, as illustrated in FIG. 2,wherein it maintains the contact 64 against the hub 58. However, whenthe speed of the flywheel and consequently of the switch element 62reaches a predetermined value, the centrifugal force acting on the arm63 causes the upper end of the arm to swing outwardly so that thecontact 64 disengages the hub 58. Of course, the speed at which the armbreaks contact with the hub depends on the stiffness of the spring, andin the preferred embodiment the spring stiffness is selected so thatcontact is maintained until approximately 1,000 RPM. Thus, whenever theengine is rotating at less than 1,000 RPM, there is an electricalconnection between the starter housing 44 and the flywheel 38, which, ofcourse, is part of the engine and functions as a ground.

The engine 16 utilizes a magneto type ignition system, which includes aprimary coil 66 having one end connected to ground, in this case theengine and its opposite end connected to breaker points 68 by aconductor 70. A condenser 72 is mounted in parallel with the breakerpoints 68'and the breaker points are grounded to the engine by a lead74, all of the above being conventional magneto ignition systemconstruction. Since the system is conventional, the secondary coil andspark plug are not illustrated.

A mower clutch switch 76 is connected to the mower clutch pedal 30, sothat it opens when the clutch pedal is released and the mower drive isdisengaged. A drive clutch switch 78 is connected in parallel with themower clutch 76 and is shiftable into its open condition when the driveclutch pedal 34 is depressed to disengage the main drive. Therelationship of the switches 76 and 78 to the mower drive and the maintraction drive is also described in greater detail in U. S. Pat. Nos.3,608,285 and 3,626,676. The parallel connected switches 76 and 78 areconnected to the ungrounded side of the primary coil 66 by means of aconductor 80, while the opposite side of the switches is connected tothe starter housing 44 by a conductor 82, which is clamped to thehousing 44 by means of one of the bolts 46.

In operation, when either the mower clutch switch 76 or the drive clutchswitch 78 is closed as a result of the mower drive being engaged or themain drive being engaged, the primary coil 66 will be shorted to groundthrough the conductor 88, the closed switch, the conductor 82, thestarter housing 44., the shaft 56, the hub 58, and the centrifugalswitch element 62, provided, of course, that the centrifugal switch isclosed, as a result of the engine being stopped or rotating at less than1,000 RPM. Thus, it would be impossible to start the engine with eitherthe mower drive or the main traction drive engaged. Obviously, when bothof said drives are disengaged, the engine can then be started, and afterthe engine reaches a predetermined speed, 1,000 RPM in the illustratedembodiment, the switch element 62 swings to its open condition to breakthe grounding circuit, so that closing ofeither or both of the switches76 Or 78 will not short out the primary coil 66.

Of course, the same or similar system can be utilized on other types ofequipment. For example, in a machine such as a rotary tiller, agrounding switch could be made responsive to the clutch which engagesthe drive to the rotating tiller element. Since such a machine does notinclude a traction drive, only a single clutch-actuated switch would benecessary. Similarly, the system could be utilized on a snow blower sothat the engine could not be started when the drive to the snow throwingelement is engaged. Obviously, the 1 system could also be utilized in alawn and garden tractor having a traction drive and a drive for anyattached implement, such as a mower or rotary tiller.

I claim:

1. In a lawn and garden machine having a mobile main frame, an internalcombustion engine having an ignition system, a working tool and meansfor drivingly connecting the engine to the working tool and including aclutch means selectively engageable and disengageable to respectivelyestablish or disestablish the driving connection, the improvementcomprising: a first switch means operatively connected to and responsiveto the condition of the clutch means so that it is open when the clutchmeans isdisengaged and closed when the clutch means is engaged; anormally. closed centrifugal switch means operatively mounted on theengine and shiftable into an open condition when the enginespeed exceedsa predetermined value; and electrical conductor means operativelyconnecting the first switch means and centrifugal switch means in seriesbetween the ignition and ground to short the ignition system when bothswitch means are closed and thereby prevent the engine from beingstarted when the clutch means is engaged.

2. The invention defined in claim 1 wherein the ignition system is ofthe magneto type and includes a pri-- mary coil, the conductor meansbeing connected to the primary coil to short the primary coil to groundwhen both switch means are closed.

3. The invention defined in claim 1 wherein the machine includes drivewheel means and means for drivingly connecting the engine to the drivewheel means and including a second clutch means selectively engageableand disengageable to respectively establish and disestablish the drivingconnection, and including a second switch means connected in parallelwith the first switch means and responsive to the condition of thesecond clutch means so that it respectively opens and closes in responseto disengagement and engagement of the clutch means, to short theignition system when either clutch means isenga'ged and the engine isrotated below said predetermined speed.

4. The invention defined in claim 3 wherein the working tool is a mowerunit and the first clutch means is disposed in the mower drive toprevent the engine from being started when the mower drive is engaged.

5. The invention defined in claim 1 wherein the engine includes a recoilstarter and a flywheel and the centrifugal switch means includes ashiftable arm connected to and rotatable with the flywheel and biasedtoward engagement with the recoil starter, the arm being swingable out.of engagement with the recoil starter in response to centrifugal forcewhen the flywheel speed exceeds said predetermined value to open saidswitch means.

6. In a machine having a mobile main frame, an internal combustionengine mounted on the frame and having a magneto ignition system with aprimary coil, a

driven element, and means drivingly connecting the en- I gine to thedriven element and including a clutch means selectively engageable anddisengageable to respectively establish or disestablish the drivingconnection, the improvement comprising: a first switch means mounted onthe frame and operatively connected to the clutch means to respectivelyopen and close in response to disengagement and engagement of the clutchmeans; a normally closed centrifugal switch means operatively mounted ona rotating engine element for shifting to an open condition in responseto centrifugal force when the rotating element reaches a predeterminedspeed; and a grounded electrical conductor means operatively connectingthe centrifugal switch means and the first switch means in series to themagneto primary coil so that the primary coil is shorted to ground whenthe first switch means and the centrifugal switch means are closed. 7.The invention defined in claim 6 wherein the engine includes a flywheel,and the centrifugal switch means is mounted on the flywheel.

8. The invention defined in claim 6 wherein the engine includes a recoilstarter and a flywheel and the v centrifugal switch means includes ashiftable arm connected to and rotatable with the flywheel and biasedtoward engagement with the recoil starter, the arm being swingable outof engagement with the recoil starter in response to centrifugal forcewhen the flywheel speed exceeds said predetermined value to machineincludes drive wheel means and means for drivingly connecting the engineto the drive wheel means and including asecond clutch means selectivelyengageable and disengageable to respectively establish and disestablishthe driving connection, and including a second switch means connected inparallel with the first switch means and responsive to the condition ofthe second clutch means-so that it respectively opens and closes inresponse to disengagement and engagement of the clutch means, to shortthe ignition system when either clutch meanS is engaged and the engineis rotated below said predetermined speed.

1. In a lawn and garden machine having a mobile main frame, an internal combustion engine having an ignition system, a working tool and means for drivingly connecting the engine to the working tool and including a clutch means selectively engageable and disengageable to respectively establish or disestablish the driving connection, the improvement compriSing: a first switch means operatively connected to and responsive to the condition of the clutch means so that it is open when the clutch means is disengaged and closed when the clutch means is engaged; a normally closed centrifugal switch means operatively mounted on the engine and shiftable into an open condition when the engine speed exceeds a predetermined value; and electrical conductor means operatively connecting the first switch means and centrifugal switch means in series between the ignition and ground to short the ignition system when both switch means are closed and thereby prevent the engine from being started when the clutch means is engaged.
 2. The invention defined in claim 1 wherein the ignition system is of the magneto type and includes a primary coil, the conductor means being connected to the primary coil to short the primary coil to ground when both switch means are closed.
 3. The invention defined in claim 1 wherein the machine includes drive wheel means and means for drivingly connecting the engine to the drive wheel means and including a second clutch means selectively engageable and disengageable to respectively establish and disestablish the driving connection, and including a second switch means connected in parallel with the first switch means and responsive to the condition of the second clutch means so that it respectively opens and closes in response to disengagement and engagement of the clutch means, to short the ignition system when either clutch means is engaged and the engine is rotated below said predetermined speed.
 4. The invention defined in claim 3 wherein the working tool is a mower unit and the first clutch means is disposed in the mower drive to prevent the engine from being started when the mower drive is engaged.
 5. The invention defined in claim 1 wherein the engine includes a recoil starter and a flywheel and the centrifugal switch means includes a shiftable arm connected to and rotatable with the flywheel and biased toward engagement with the recoil starter, the arm being swingable out of engagement with the recoil starter in response to centrifugal force when the flywheel speed exceeds said predetermined value to open said switch means.
 6. In a machine having a mobile main frame, an internal combustion engine mounted on the frame and having a magneto ignition system with a primary coil, a driven element, and means drivingly connecting the engine to the driven element and including a clutch means selectively engageable and disengageable to respectively establish or disestablish the driving connection, the improvement comprising: a first switch means mounted on the frame and operatively connected to the clutch means to respectively open and close in response to disengagement and engagement of the clutch means; a normally closed centrifugal switch means operatively mounted on a rotating engine element for shifting to an open condition in response to centrifugal force when the rotating element reaches a predetermined speed; and a grounded electrical conductor means operatively connecting the centrifugal switch means and the first switch means in series to the magneto primary coil so that the primary coil is shorted to ground when the first switch means and the centrifugal switch means are closed.
 7. The invention defined in claim 6 wherein the engine includes a flywheel, and the centrifugal switch means is mounted on the flywheel.
 8. The invention defined in claim 6 wherein the engine includes a recoil starter and a flywheel and the centrifugal switch means includes a shiftable arm connected to and rotatable with the flywheel and biased toward engagement with the recoil starter, the arm being swingable out of engagement with the recoil starter in response to centrifugal force when the flywheel speed exceeds said predetermined value to open said switch means.
 9. The invention defined in claim 6 wherein the driven element comprises a mower unit and the first clutch means is disposed in the mower unit drive to preveNt the engine from starting when the mower drive is engaged.
 10. The invention defined in claim 9 wherein the machine includes drive wheel means and means for drivingly connecting the engine to the drive wheel means and including a second clutch means selectively engageable and disengageable to respectively establish and disestablish the driving connection, and including a second switch means connected in parallel with the first switch means and responsive to the condition of the second clutch means so that it respectively opens and closes in response to disengagement and engagement of the clutch means, to short the ignition system when either clutch meanS is engaged and the engine is rotated below said predetermined speed. 